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February 20, 2012

New Diet Pill Side-Effects Under Scrutiny By FDA Regulators

by editor

A weight-loss drug currently under a second review from the Food and Drug Administration (FDA) is causing concerns that it may be responsible for birth defects and heart problems, according to documents released by the agency on Friday.

The drug, developed by Vivus, was rejected by the agency in 2010, largely because of those risks. A committee of outside advisers to the FDA will meet this week to reconsider whether the drug, called Qnexa, should move forward in the approval process, reports Andrew Pollack for the NY Times.

Obesity specialists and patient advocates agree there is a huge need for obesity drugs to bridge a treatment gap between diet and exercise, which do not work for many people, and bariatric surgery, which is expensive and not suitable for those with specialized medical conditions.

The FDA, however, has been cautious with approving diet drugs, in part because with two-thirds of American adults overweight or obese, such drugs might be used for a long time by millions of people.

There is an FDA Advisory Panel meeting this month that is tasked with combing through 2-years´ worth of clinical data. When Qnexa was last reviewed, the Agency only had 1-year´s worth to examine.

The Advisory Panel will have to discuss and vote on whether to recommend supporting or declining the obesity drug after carrying out an overall benefit-risk assessment, reports Christian Nordqvist for Medical News Today. The FDA can choose to accept or reject the non-binding decision but this hardly ever happens. Therefore, Qnexa´s future, at least this time around, depends on what happens this week.

When the FDA previously turned Qnexa down, it asked Vivus for more clinical data on the medication´s potential impact on major adverse cardiovascular events and birth defects.

One question the advisory committee will be asked to consider is whether Vivus should be required to conduct a large new clinical trial before the final approval is given to assess whether the drug increases the risk of heart attack. Facing more delays, possibly by several years, Vivus has proposed doing the study after approval.

Studies also show that the use of topiramate during pregnancy increases the risk of oral clefts, such as cleft lip, by a factor of two to five, according to the FDA staff review released last week. That is a concern, the reviewers said, because “the major consumers of weight-loss drugs are women of childbearing potential,” leading to “the potential for large numbers of pregnancy exposures.”

Qnexa was picked as the most suitable weight loss drug because of the high level of weight loss reported in company studies, with an average of more than 10 percent total body mass reduced among participants of the study, USA Today is reporting.

Reviewers for the FDA were still guarded in their approval. “Overall, the long-term clinical impact of the observed modest improvements in comorbidity outcomes is uncertain, particularly in a population with higher risk of CV adverse events,” the FDA wrote, referring to cardiovascular events such as heart attacks.

The main cardiovascular concern is that Qnexa increases heart rate. Still, the reviewers did say that the effect of the drug in lowering blood pressure was “somewhat reassuring.”